Check Prime Number – C SOURCE CODING
PRIME NUMBER LOGIC:
A Prime Number Can Be Divided, Without a Remainder, Only By itself and By 1.
Example:
17 Can Be Divided Only By 17 And By 1.
SOME FACTS:
The Only Even Prime Number is 2. All Other Even Numbers Can Be Divided By 2.
If the Sum of A Number’s Digits is a Multiple of 3, that Number Can be Divided By 3.
No Prime Number Greater Than 5 Ends in a 5. Any Number Greater Than 5 That Ends in a 5 Can Be Divided By 5.
Zero and 1 Are Not Considered Prime Numbers.
Except for 0 and 1, a Number is either a Prime Number Or A Composite Number. A Composite Number Is Defined as Any Number, Greater Than 1, That is Not Prime.
To Prove Whether a Number is a Prime Number, First Try Dividing it by 2, and see if you Get a Whole Number. If you do, it can’t be a Prime Number. If You Don’t Get a Whole Number, Next Try Dividing it by Prime Numbers: 3, 5, 7, 11 (9 is divisible by 3) and so on, always dividing by a prime number (see table below).
Here is a Table Of All Prime Numbers Up To 1,000:
|
2
|
3
|
5
|
7
|
11
|
13
|
17
|
19
|
23
|
29
|
31
|
37
|
41
|
43
|
47
|
53
|
59
|
61
|
67
|
71
|
73
|
79
|
83
|
89
|
97
|
101
|
103
|
107
|
109
|
113
|
127
|
131
|
137
|
139
|
149
|
151
|
157
|
163
|
167
|
173
|
179
|
181
|
191
|
193
|
197
|
199
|
211
|
223
|
227
|
229
|
233
|
239
|
241
|
251
|
257
|
263
|
269
|
271
|
277
|
281
|
283
|
293
|
307
|
311
|
313
|
317
|
331
|
337
|
347
|
349
|
353
|
359
|
367
|
373
|
379
|
383
|
389
|
397
|
401
|
409
|
419
|
421
|
431
|
433
|
439
|
443
|
449
|
457
|
461
|
463
|
467
|
479
|
487
|
491
|
499
|
503
|
509
|
521
|
523
|
541
|
547
|
557
|
563
|
569
|
571
|
577
|
587
|
593
|
599
|
601
|
607
|
613
|
617
|
619
|
631
|
641
|
643
|
647
|
653
|
659
|
661
|
673
|
677
|
683
|
691
|
701
|
709
|
719
|
727
|
733
|
739
|
743
|
751
|
757
|
761
|
769
|
773
|
787
|
797
|
809
|
811
|
821
|
823
|
827
|
829
|
839
|
853
|
857
|
859
|
863
|
877
|
881
|
883
|
887
|
907
|
911
|
919
|
929
|
937
|
941
|
947
|
953
|
967
|
971
|
977
|
983
|
991
|
997
|
|
PRIME NUMBER PROGRAM
#include <stdio.h>
#include <conio.h>
int main()
{
int i,j=2,ch=0;
clrscr();
printf(“\nENTER ANY NUMBER”);
scanf(“%d”,& i);
while(j < =i/2)
{
if(i%j==0)
{
printf(“%d IS NOT PRIME”,i);
ch=1;
break;
}
else
{
j++;
}
}
if(ch==0)
{
printf(“%d IS PRIME”,i);
}
}
Check Prime Number - C SOURCE CODING
